[chevyrestoguy]

I've never done that kind of swap-over, but off the top of my head, you'll have to figure out front leaf spring mounts, a transfer case mount, cut a hole in the floor for the hi-low selector, possibly re-mount the '79 rear axle due to the pinion offset, and figure out driveshaft lengths. I think you'll be surprised at just how much stuff off of the '79 you can use. Chevy was really good about making their stuff usable on a wide range of vehicles. I'm pretty certain that there's been some guys on this site that have done this swap, and I hope they can post up with some good tips for you.

I would consider just using the parts off of the '79 and not doing a entire chassis swap between the '65 and the '79. That poses a whole new set of problems with cab mounting, wheelbase, and track width.